1. Field of the Invention
The present invention relates to a sheet feeding device including a sheet feed member. It is based upon Japanese Application no. 10-23480 filed on Feb. 4, 1998 and Japanese Application no. 98-6873 filed on Dec. 3, 1998, both of which are hereby incorporated by reference.
2. Discussion of the Background
An image forming apparatus (e.g., copiers, facsimiles, printers or similar image forming apparatus) uses various kinds of sheet feeding devices. For example, a sheet feed member may cooperate with a friction pad feed system to feed sheets by using a frictional force between the sheet feed member and the friction pad. Japanese Laid-Open Patent Publication No. 3-116325 discloses such a sheet feed mechanism having a plurality of cams which are coaxially fixed to both ends of a sheet feed roller. However, that configuration requires the presence of a part devoted exclusively thereto, and so the cost of the apparatus inevitably increases.
In the above sheet feed mechanism, the cams separate the sheet feed roller from a friction pad after a part of a top sheet fed from a stack and contacts the friction pad. A trailing edge of the top sheet is held between the friction pad and the sheet feed roller. However, it is possible that the sheet may be improperly fed because of a change in a state of contact against the sheet.
Moreover, as shown in FIG. 11 and FIG. 12, it is possible that the sheet P, which is fed by the sheet feed roller 1 and the friction pad 3, may be frictionally charged by the cams 2, and a toner image may be improperly transferred (e.g., transfer hollow) on the sheet P.